1. Field of the Invention
The present invention relates to an electrical connector, and more particularly to an electrical connector having contacts for improved characteristic impedance.
2. Description of Related Art
At present, an electrical connector usually includes an insulative housing and a plurality of contacts received in the insulative housing, and each contact comprises a soldering portion soldered with a wire, a mating portion contacted with corresponding contact of a complementary connector, and a middle portion located between the soldering portion and the mating portion. The soldering portion, a mating portion, and the middle portion have a same thickness, thus when the mating portion contacts with a complementary contact, the total thickness of a mating section of the complementary contact and the mating portion is greater than the thickness of the middle portion. When the soldering portion is soldered with the wire, the total thickness of the soldering portion and the wire along an up-to-down direction is also larger than the thickness of the middle portion. Therefore, as the electrical connector is in a working state, mutation phenomenon of the characteristic impedance of the contact may be present, that is, the characteristic impedance of the soldering portion and the mating portion is smaller than the characteristic impedance of the middle portion. Due to the occurrence of the above situation, stability of signal transmission of the electric connector will be affected.
U.S. Pat. No. 7,088,200, issued to Bartley et al. on Aug. 8, 2006, discloses a method and structure to control common mode impedance in fan-out regions for printed circuit board applications. A differential pair transmission line includes a narrow signal trace portion in the fan-out region and a wider signal trace portion outside of the fan-out region. The narrow signal trace portion in the fan-out region has an increased thickness relative to the wider signal trace portion.
Hence, an electrical connector with improved contacts for characteristic impedance is desired.